1. Field of the Invention
The invention relates to a method and an apparatus for data transmission in a system having n transmission channels, a transmitting and a receiving station, m channels (n.gtoreq.m.gtoreq.0) being used for data transmission, and a partial data transmission being effected over each of the m channels.
An exchange of data between two data stations is typically enabled by means of a modem over a data channel for remote data transmission. However, the transmission rate in such methods is dependent on the bandwidth of the channel.
In modern systems, such as ISDN, a connection with a transmission rate of 64 kbit/sec can be made available to a subscriber. So-called multiplex connections with 30 such channels are also provided. In order to increase the transmission rate of 64 kbit/sec, a data packet to be transmitted can, for instance, be divided into individual partial data packets and transmitted simultaneously over a plurality of channels. Thus a transmission rate over 30 channels of up to 1920 kbit/sec is possible.
However, a disadvantage of the above-described method is that the individual channels have different delay times in data transmission, so that the partial data signals that arrive at the receiver are staggered in time relative to one another.
2. Summary of the Invention
It is accordingly an object of the invention to provide a method and an apparatus for data transmission, which overcome the hereinafore-mentioned disadvantages of the heretofore-known methods and devices of this general type and which enable data transmission over a number of channels to be carried out as simply as possible.
With the foregoing and other objects in view there is provided, in accordance with the invention, in a method for data transmission in a system having n transmission channels, a transmitting and a receiving station, m channels (n.gtoreq.m.gtoreq.0) for transmitting data, and each of the m channels effecting a partial data transmission, the improvement which comprises ascertaining a time offset with the receiving station over the transmission channels during an initializing phase, by simultaneously transmitting a predetermined starting value from the transmitting station to all of the channels; transmitting a confirmation signal from the receiving station over at least one of the channels to the transmitting station, if all of the channels in the receiving station have received the predetermined starting value; transmitting a numerical sequence from the transmitting station over all of the channels, beginning with a predetermined value, after receiving the confirmation signal; and ascertaining and taking into account the time offset between the various channels for an ensuing data transmission at the receiving station from the relative offset of the data values received in the various channels, after a starting value having a different value than the predetermined starting value has been received over all of the channels.
In accordance with another mode of the invention, there is provided a method which comprises generating a numerical succession with a pattern generator circuit in the transmitting station.
With the objects of the invention in view, there is also provided in a system having n transmission channels, a transmitting and a receiving station, m channels (n.gtoreq.m.gtoreq.0) for transmitting data, and each of the m channels effecting a partial data transmission, an apparatus for data transmission, comprising an address memory, a data memory and control means in the receiving station; the address memory storing ascertained time offset values to form offset addresses; the data memory sequentially storing received data under control of the control means; the control means controlling addressing and reading out of the data memory with the offset addresses stored in the address memory; and the control means assigning the read-out data to an output channel.
In accordance with a concomitant feature of the invention, there is provided a pattern generator circuit in the transmitting station for generating a numerical succession.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and an apparatus for data transmission, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.